Projection system of high efficiency

Abstract

There is disclosed a light system for projection of images onto a visual read out surface such as a screen or photo receptor recording device such as a xerographic drum. The projection system employs a nonpoint light source which forms a light beam of nonuniform intensity. The light beam is passed through a conical light pipe with a high degree of internal reflection which diffuses the light beam, thereby reducing the nonuniformity of the light beam and also collimates the light beam by internal reflections. The collimated light beam is then modulated with imaging information and is focused onto a visual readout surface such as a screen or a recording device surface.

What is claimed: 
     
       1. An image projecting means including: (1) light beam generation means to produce a non-uniform light beam and for projecting said light beam along a projection axis;   (2) light beam transmission means receiving said non-uniform light beam from said light beam generation means and comprising light pipe means, said light pipe means having internal walls with a high degree of internal reflection and tapered at an angle in the range from 1° to 60° along the projection axis of said light beam, the extent of said light beam transmission means in the direction of said projection axis completely surrounding the projection axis coextensive therewith;   (3) light beam bifrucation means to divide said light beam into at least two subidvided light beams and including a plurality of optical stops formed thereon, said light beam bifrucation means comprising a plurality of light pipes;   (4) an imaging member to receive said subdivided light beams and to cause imagewise phase modulation of a portion of said received subdivided light beams, said imaging member being reflective; and   (5) objective lens means to receive said subdivided light beams and to focus the portion of said non-modulated sub-divided light beams onto said plurality of optical stops and to focus the modulated portion of said subdivided light beams onto a display surface, said optical steps comprising exit apertures of said light pipes.   
     
     
       2. An image projecting means including: (1) light beam generation means comprising: (a) concave reflector means having a light reflective surface defined by a surface of revolution of a plane curve about a central axis; and   (b) a nonpoint light source position substantially at the focal point of said reflector means, said generation means characterized by the development of a light beam of nonumiform intensity;     (2) condensing lens means;   (3) light beam transmission means receiving said light beam from said condensing lens means and comprising light pipe means with internal walls having a high degree of internal reflection and tapered at an angle in the range from 1° to 60° along the axis of propagation of said light beam, said light pipe means being the only means effecting random diffusion of said light beam by internal reflections, thereby substantially reducing the intensity nonuniformity of said light beam the extent of said light beam transmission means in the direction of said projection axis completely surrounding the projection axis coextensive therewith;   (4) light beam bifrucation/means to receive said light beam from said light beam transmission means and bifrucate said light into a plurality of light beams, said light beam bifrucation means comprising divergent individual light pipes terminating in spaced-apart, parallel alignment at light transmitting windows on the inclined surface of a totally reflecting prism;   (5) an imaging member having a deformable reflective surface for imaging of electromagnetic radiant information; and   (6) objective lens means to focus said plurality of light beams on said reflective surface of said imaging member and for directing zero order reflected light therefrom to said light source and higher order reflected light to visual readout means.   
     
     
       3. The image projecting means of claim 2 wherein said divergent individual light pipes are flat planar sheets folded at about 45° to their longitudinal axis at an intermediate position and terminating with an end beveled at about 45° to provide reversal of the direction of propagation of said parallel light beams. 
     
     
       4. The image projecting means of claim 3 wherein said objective lens means directs zero order reflected light into said light pipes and higher order reflected light between said light pipes to focus on a distant screen. 
     
     
       5. The image projecting means of claim 2 wherein said objective lens means directs said zero order reflected light into said light transmitting windows and higher order reflected light onto the reflecting portions of said totally reflecting prism. 
     
     
       6. The image projecting means of claim 5 including projection lens means to receive said higher order reflected light and focus said light on a remote light receiving means. 
     
     
       7. The image projecting means of claim 5 wherein said reflecting portions of said prism comprises spaced-apart rectangularly shaped mirrors. 
     
     
       8. An image projecting means including: (1) light beam generation means comprising: (a) concave reflector means having a light reflective surface defined by a surface of revolution of a plane curve about a central axis; and   (b) a nonpoint light source positioned substantially at the focal point of said reflector means, said generation means characterized by the development of a light beam of nonumiform intensity along a projection axis;     (2) condensing lens means;   (3) light beam transmission means receiving said light beam from said condensing lens means and comprising light pipe means with internal walls having a high degree of internal reflection and tapered at an angle in the range from 1° to 60° along the axis of propagation of said light beam, said light pipe means being the only means effecting random diffusion of said light beam by internal reflections, thereby substantially reducing the intensity nonumiformity of said light beam, the extent of said light beam transmission means in the direction of said projection axis completely surrounding the projection axis coextensive therewith;   (4) light beam bifrucation means to receive said light beam from said light beam transmission means and bifrucate said light into a plurality of light beams, said light bifrucation means comprising a plurality of parallel, spaced-apart, rectangular mirrors at angular orientation to intercept said light beam and direct a plurality of relatively flat beams of light to said lens means;   (5) an imaging member having a deformable reflective surface for imaging of electromagnetic radiant information; and   (6) objective lens means to focus said plurality of light beams on said reflective surface of said imaging member and for directing zero order reflected light therefrom to said light source and higher order reflected light to visual readout means.